Jane Seymour feared the worst as she opened the hospital letter. She had gone through two breast operations in recent years and feared that it would tell her that cancer cells were back, and the remaining two thirds of her right breast would need to be removed.

But this isn't what the letter said.

It told her that the hospital was "going through all the records" of all the patients of her surgeon, Ian Paterson, a respected consultant who operated at five hospitals in the West Midlands, after finding "some irregularities".

The hospital invited her to speak to one of its other consultants to discuss her surgery. At that meeting last month, the 56-year-old was told that she had had only benign, non-cancerous tissue, despite the operations and years of physical and emotional trauma she endured as a result of them.

Jane's experience is not unique: she is among 450 women who have been recalled following "irregularities" with their medical notes from benign breast surgeries performed by Paterson at the Spire Little Aston and Spire Parkway clinics between 2004 and 2011. Jane had found a pea-sized lump in her right breast in 2006 and was referred by her local GP to Paterson. "He was a very charming man," Jane told the Guardian. "So genuine, and full of concern; I put my faith in him, and trusted his advice."

But the doctor's disclosures at the recall appointment changed everything. "For six years I've been living under the fear that I would get cancer … I've had two operations – there's a massive dent in the side of my breast – but there was nothing ever wrong with me."

Looking at Jane's scans, and the results of a needle-aspiration, she says, Paterson diagnosed her lump as pre-cancerous – without performing a core biopsy. "I was told in no uncertain terms that if I didn't have the operation, then I would get breast cancer," says Jane, a mother of three. "I was terrified, and of course agreed to surgery."

Last week, the GMC put an interim suspension on Paterson's licence, but said it could not disclose details of the order because the investigation is ongoing. Kashmir Uppal, a solicitor from Thompsons representing 100 of Paterson's concerned patients, said she was in close contact with the GMC investigating officer. "It [the suspension] is not a finding based on fact," she says. "The interim order panel have decided that it is necessary for the protection of members of the public, it is in the public interest and in Mr Paterson's own interest to suspend him until further notice."

A number of the women the Guardian spoke to gave details of their recall appointments with Spire consultants. They said they were told that their medical notes and test results gave no indication of pre-cancerous cells in the breast tissue, and that surgery had been unnecessary.

Some patients said they were also told of "coding issues" with their files. When pressed, the consultant at the recalls explained that Paterson had wrongly coded for surgeries that were not needed, and in some instances, procedures he did not perform, some of the women said.

The GMC has referred the case to West Midlands police, which said it was "working closely with the GMC to assess the allegations and determine whether a criminal investigation is necessary".

In a statement late Tuesday, Paterson, who is being represented by the Medical Defence Union, said: "I am co-operating fully with the GMC investigation and cannot comment on any of the issues raised because of my duty of patient confidentiality and the ongoing investigation."

In a statement, Paula Naylor, hospital director of Spire Parkway hospital, said, referring to the coding errors: "We have referred this matter to the General Medical Council so they can investigate Mr Paterson's fitness to practice, but cannot speculate on the outcome. Clearly we are looking at what we can learn from these events, but our priority right now is to hold consultations with those patients affected and to provide them with accurate information as quickly as possible."

The concerns that led to the recall letters surfaced amid an ongoing investigation by the GMC into Paterson's controversial "cleavage-sparing" mastectomy, performed in five hospitals across the West Midlands. In 2007, Heart of England NHS Trust conducted a review of the technique, which leaves a small amount of breast tissue around the cleavage for cosmetic reasons.

At the time, Dr Aresh Anwar, medical director of the trust, said: "An external review highlighted that this was not a usual procedure and that Mr Paterson had not followed guidelines to introduce a new technique. It required closer scrutiny to establish whether it represented best practice."

In December 2007, Paterson was banned from using the technique, and the trust "began a process of identifying patients who may have undergone this procedure". Some 700 of these NHS patients were urgently recalled last summer, for "a review of their treatment and care".

On her daughter's 18th birthday, Jane underwent her second operation with Paterson, as the original scar tissue had become diseased. "It wasn't nice to look at and it wasn't very pleasant to feel," she says. "I couldn't bear my husband touching me, I wouldn't even let him look. So he went elsewhere. Now we're getting divorced; I have to laugh about it, I've had my tears and tantrums."

Last month, Jane says she was told by Steven Thrush, a specialist breast consultant at Spire, that the abnormal cells originally detected by Paterson were consistent with a benign lump, which would have dissipated if left alone.

"I just sat there, dumbfounded," she says. "Two big operations and a third of my boob removed, for nothing. I was absolutely livid, everything I've been through and never should have happened. It has had a ripple effect for my whole family. My son told me that he's been petrified every day since I had the first operation. That was six years ago."

A lumpectomy can cost between £2,000 and £6,000 with the added expense of mammograms, ultrasound scans and the initial consultation. Jane, like many of the women interviewed, says she was also encouraged by Paterson to attend several follow-up appointments and undergo extensive scanning. In her recall appointment, she says she was told this, too, was unnecessary.

At 32, Marie Bailey was one of Paterson's youngest patients at the Spire hospitals. She sees herself now as "one of the lucky ones" for having avoided a lumpectomy.

In 2007, Marie was seen by Paterson for suspected Paget disease, a rare form of breast cancer involving the surface skin. She was put under general anaesthetic for a core biopsy and woke to Paterson telling her the results were abnormal. "I was so scared as Paget disease is very aggressive," she says. "I thought that was it. I thought I was going to die."

After an agonising week spent waiting for more information with her husband and young son, Marie was told by Paterson that everything was fine. The swelling turned out to be eczema, a condition to which she has always been prone.

In her recall appointment at the Spire Parkway, Marie says the consultant, Steven Thrush, explained that her mammogram had been normal and therefore a general anaesthetic and core biopsy were "inappropriate", although it was important that a correct diagnosis was eventually reached. "Mr Paterson put me through something I didn't need," she says.

A total of 327 of the women have now had their recall appointment, but more than 100 are still waiting.

Gemma has been looking at the Spire letter on her kitchen table for four weeks; every day she wills the postman to bring her another, with details of her recall appointment.

"I know what they will say, I found out by seeing another doctor," she says. "My lump wasn't cancerous at all and a simple biopsy would have saved me the deformity that I've been left with."

Her slim frame is dwarfed by the baggy tops she has worn every day since her lumpectomy in 2010. She cannot bear people looking at her chest; until now, a symbol of survival. "If I had cancer and he'd saved me, then I would have to tolerate the way I look, because that's part of the illness," she says. "But I didn't have the illness, so why have I been left with the wounds?"

Gemma found a lump in her left breast at Christmas in 2009. A single mother with a long family history of fatal cancer, she immediately went to see her GP. Unable to face the six-week NHS wait, she went to the Spire Parkway and was recommended Mr Paterson. "My son was coming up to his 18th birthday, and I just thought that I wouldn't even live long enough to be there," she says. "I've lost a lot of my family to cancer, and I was worried, because there would be no one to watch out for him."

Like many of the women, she felt instantly comfortable with the Glaswegian doctor, who lives in Edgbaston. "He told me the scan had shown there was something sinister in my breast, and it needed to come out," she says. "He just kept using the word 'sinister'."

Gemma agreed to the lumpectomy, unaware that a biopsy is normally performed alongside mammogram and ultrasound scans to provide definitive evidence of pre-cancerous cells.

A week after the operation Paterson, she says, told her that she was "a very, very lucky young lady", and that the cancer had gone. "I remember walking out of there, and telling my friend that I was going to be fine," she says. "We were both stamping in the car park, hugging and crying. But now I'm crying because I'm angry, because I didn't even need the surgery."

Since the operation, Gemma, 44, has suffered severe anxiety and depression, and she cannot come to terms with how she now looks. "They've left substantial scarring, and I'm not the same on both sides," she says. "I got married in September, but my husband has never seen the scar. Maybe if I got it fixed … but at the moment it is too embarrassing."

Gemma is desperate to get the £6,000 reconstructive surgery, but because she gave up her job as an accountant for six months following the lumpectomy, she no longer has the savings to pay for it. Her medical insurance increased after Paterson's surgery, and she had to cancel the payments and "just cross [her] fingers that she wouldn't get cancer".

In her statement, Paula Naylor at Spire said: "Spire Healthcare, in conjunction with GMC and the Heart of England NHS Foundation Trust [Heft], is continuing to investigate the practice of Ian Paterson.

"Supported by a team of independent consultant breast surgeons, we have reviewed the medical records of Ian Paterson's patients who underwent specific procedures for benign [non-cancerous] breast conditions. We are notifying every patient whose notes have been reviewed and are offering each a face-to-face consultation about their care.

"This is a review of patients with benign breast conditions. Our priority is always patient care and we do not believe there is any immediate health risk. However, any patient treated by Ian Paterson who has immediate concerns or questions should call a dedicated phone line, 0800 044 3134, and arrange to speak with our professional medical staff.

"Mr Paterson is the subject of an investigation by the GMC, supported by the Heart of England Foundation Trust and Spire Healthcare. Whilst our investigations have revealed some irregularities in his practice that resulted in his suspension in August 2011, we do not want to compromise the GMC's investigation by commenting further at this stage. We are offering every patient of Mr Paterson who was part of this review a meeting with a consultant breast surgeon in order to answer any questions they may have regarding their treatment by Mr Paterson."

Asked what measures were in place to monitor surgeons and whether these applied to Paterson, Naylor said: "One of the requirements of receiving practising privileges to practise privately is that every doctor is required to undergo annual appraisal arranged through their employing NHS trust, and this process included Mr Paterson. With the introduction of professional revalidation of all doctors on 3 December this year, every doctor will be required to undergo strengthened medical appraisal and this will inform the decision by the General Medical Council to revalidate them every five years."

Breast surgery is extremely traumatic, and for many women the emotional damage is more complex than the scars it leaves behind. "It is a mental cruelty, apart from the physical; my life has never been the same and it never will be the same," says Gemma.

"The shock of finding out that I didn't need the surgery is on a par with thinking that I had cancer in the first place. I am devastated."

The GMC said: "Dr Ian Paterson's registration is currently suspended, following an interim orders panel meeting on 29 October 2012. This means the doctor cannot work as we investigate concerns about his fitness to practise."